[derekbitt]

I have basically the same truck, i dont have this problem, but try to eliminate the pvc valve possiblity and then at the top of the engine is the fuel injector system. i can imagine both of these may make buzzing. you could get an engine stethescope or a piece of rubber hose to listen to a specific part of the engine to narrow the search. could it be a fast mechanical sound or is it more of an electrical buzzing?